Grab



GRAB

2 Sheets-Sheet lA/Vf/VIDP ATIOPA/EY Filed March 30. 1928 March 19, 1929. D. J. QBARNARD GRAB Filed March 30, 1928 2 Sheets-Sheet 2 Patented Mar. 19, 1929.

, UNITED AT PA' 'E ToF DUDLEY JAMES 'BARNARD, or BARKING, ENGLAND.

Application filed-March so, 1928, Serial no. 266,670, and in Great Britain March 28, i927 This invention relates to grabs'of the type in which all movementsfof the grab are usually efiected by a single chain or rope and in which the grab is supported by a button secur'ed to the chain while the tripv or unlocking mechanism is being disengaged from the tipping ring supported iirom'the jib of the crane andwhilethe grab is being lowered on to'the material tobe raised. .7 A .r i L i It has beenfound in; practice. that there is considerable diificnlty in effectively securing the button to a wirerope and it is the object of this invention to, provide an improved def vice by means of, which the buttoniisv ren dered unnecessary} 5,-1 I a In the accompanying drawings which illustrate thisinvention :Figure 1 is aside View offfal grab showing the parts in the position they occupy when the grab is supported by) the hauling rope. Figure 2 is a side View of the head ofa. grab showing the parts in the position they occupy whenthe, grab is closed and supportedby the tipping ring.. Figure 3 i s, a front view of Figure 2 partly in section on line mw of Figure 4:. igure 4 is a plan view "on lin e w 'w of Figure 3. Figure 5 is a similar view to Figure 2 the bucket sec tions beingin the openposition. igure 6 is a front elevation of the operative member, and Figure? is a plan thereof.

"In the drawings1'and2 are the bucket sections pivotedfon independent pivot pins 3,74 on a transversefcross beam 5 upon-which are mounted the axles "61 forthe lower sheaves 7, 8. Spreader arms?) are arranged ateaoh corner of the grab t-heirwupper ends being pivoted on independent; pivot pins "10, 11

securedin'brackets carried bythe block'plates' 12 which constitute the head of the grab, said plates beingsuitablyspacedapart and carrying between them the axle 13 "of the sheaves 14c. Centrally disposed between the two inner block plates 12 is a thimble15 preferably formed'in two arts. The exterior of the thimble 15 is preierably of rectangular I form so as to enable it tofit and be firmly secured to and between the inner block plates 12 and the interior of cylindrical form so as to permit the sliding-or operative member 16 to reciprocate therein."

v The trip mechanism comprises a pair. of hook-shaped elements 17 provided with pins 18 slidablymounted in slots l9'provided in lugs 20 on the thimblef15 and the lower ends of said element-s, areprovided with inwardly disposed i projections j' 21 adapted to pass through {slots 2p1' ovided in the thimble 15 FICE;

vided with a cross bar23adapted to coact with and be gripped at each end of the bar byfour lugs or projections'24, constituting two pairs of gripper hooks. The upper ends of each pair of-spreader arms 9' and the opposed hinged portions of the bucket sections 1 and 2 are preferably provided with inter- 'is being lifted by the hauling rope 28, the

iengaging'toothedmembers 25, 26 to assist in I maintamlng'the balance of the grab when i crossbar. 23 is located below and out of e'n-.

gagement with the under faces of the gripper hooks 24 as shown in Figure 1. WVh'en the hook-shaped elements 17 are in engagement with the tipping ring the operative member cross-bar 23 isldrawn up aga-in'stthe under fae'es'of the gripper hooks 24: as shown in Figure 2; It now the rope 28 is paid out the bucket sections 1 and 2 begin to open and the 16 isflift-ed by the projections 21 and the 1 of thejspreader arms 9 decreases,"which takes place as the bucket sections pass into the fully.

open positionythe space between the grippingfaces of the gripper hooks increases same, and in order to avoid the sudden jar byv a pair of spring pressed pins '29 slidably drawn in the buckets close slightly. and cause and the-crossbar '23 is drawn inbetween the gripper hooks 24 to grip the cross-bar 23.v i

7 With the parts in this position the grab may be drawn upwardly to release the; hook shaped elements 17 from the tipping ring 27 andlowered on to thematerial to be raised. When in this'position the haulin ropeis paid. out, the weight of the grab eing removed from the spreader arms, the cross-bar drops free from I between the" grippers hooks i a mounted in lugs or brackets provided on'the v block plates '12. When thehauling rope is this dropping movement being assisted by the spring controlled pins 29. The grab may now be closed and raised.

.- What I claim is 1. In a grab of the kind herein described having a cross beam, a sheave block carried thereby, means mounted on the head of the grab comprising a pair of block plates, a centrally disposed thimble mounted between said plates, a member slidably arranged within said thimble, a cross-bar on said slidable member and through which the hauling rope is adapted to pass to the sheave block, a pair of oppositely disposed hook-shaped elements pivotally mounted on the block plates the lower ends 0; said hook-shaped elements being arranged to project through apertures provided in the thimble and sliding memher, and means on the spreader arms adapted to coact with the cross-bar on the sliding member.

2. In a grab ot' the kind herein described having a cross-beam, a sheave block carried thereby, a combination of devices on the head of the grab comprising a pair of block plates, a centrally disposed thimble mounted between said plates, a member slidably arranged within said thimble and through which the hauling rope is adapted to pass to thesheave block, slots provided in said thimble, a pair of oppositely disposed hookshaped elements pivotally mounted insaid slots, vertically disposed slots provided in the thimble and sliding member through which the lower ends of said hook-shaped elements are arranged to project, lugs provided on said block plates, a pair of spring pressed pins slidably mounted in said lugs the lower ends of said pins being arranged to press against the cross-bar, and gripper hooks formed on the spreader arms adapted to coact with the cross-bar on the sliding mem ber. V

3. In a grab of the kind hereinv described having a cross-beam, a sheave block carried thereby, a combination of devices on the head of the grab comprising a pair of block plates, a centrally disposed two part thimble mounted between said plates, a tubular member slidably arranged within said thimble, a cross-bar on the lower end of said tubular member and through which the hauling rope is adapted to pass to the sheave block on the cross-beam, slots provided in said thimble,

a pair of oppositely disposed hook-shaped 7 elements pivotally mounted 1n said slots,

sections with the head of the grab, said head comprising a pair of block plates, sheaves carried thereby, a centrally-disposed two part thimble mounted between said plates, a tubular member arranged within said thimble, a

cross-bar on the lower end of said tubular member and through which the hauling rope is adapted to pass to the sheave block on the cross-beam, oppositely disposed lugsforin'ed on said thimble, slots formed in said lugs, a

pair of hook-shaped elements pivotally" mounted intsaid' slots, vertically disposed slots provided invthe thimble and sliding ,member, means on the hook-shaped elements adapted to enter'the slots in the thimble and sliding member, spring controlled means located between the block plates adapted to ,coaot with the crossbar, and gripper jaws formed by "and between the ends of the spreader arms adapted to coact with the crossbar on the sliding member,

DUDLEYJAMES BARNARD, 

